1. Field of the Invention
The present invention relates generally to a focusing device, and more particularly, to an automatic focusing device providing automatic focusing function and being typically used in a digital camera module.
2. Description of Related Art
In a digital camera, a focusing device is one kind of mechanism which can be used for adjusting a distance between the lens element and the image pickup device. Thereby, when photographing objects at different distances from the camera, a clear image is obtained. A typical focusing device of a camera includes a driving mechanism, a lens mount, a lens barrel, and a lens element received in the lens barrel. A curved guiding groove is often defined in an engaging interface between the lens barrel and the lens mount. The driving mechanism drives the lens barrel to move along the guiding groove relative to the lens mount so that a distance between the lens element and an image pickup device is changed. However, the curved guiding groove is difficult to make. That is, manufacturing of the guiding groove is both time-consuming and expensive.
What is needed, therefore, is a focusing device of a camera having a simple structure.